The present disclosure relates to the dispatching of lots in semiconductor processing. More particularly, the present disclosure relates to displaying, for review by an operator, the dispatching logic of semiconductor processing tools.
In semiconductor fabrication, each semiconductor is formed as part of a lot or group of semiconductors (hereinafter “lot”). The semiconductor lot is processed by a number of differing processing tools.
The scheduling or dispatching of the semiconductor lots to the processing tools is a dynamic process. For instance, conditions can change in the manufacturing process, the raw materials, the processing tools, and other variables, which leads to a need for dynamic dispatching of the semiconductor lots to the processing tools.
Each processing tool performs a specific manufacturing process to the semiconductor lot in accordance with one or more process rules. The process rules are enforced by a service manager, commonly referred to as a real time dispatch service manager or “manager”. The service manager is an automated system that makes decisions regarding the appropriate dispatching steps to take, for instance, which tool a particular lot should be conveyed. Also, the service manager takes into account override conditions or filters that have been input by operators.
The service manager applies the dispatching rules based on the operational characteristics of each tool and how it relates to a given lot. The dispatching rules can remove lots from a dispatching list, (i.e., a listing of lots to be processed by tools) for many reasons. These reasons include tool setup optimization, waiting for batch logic updates, or compensating for work-in-progress (WIP) balancing requirements across the manager.
In some cases, the dispatching rules and/or filters deliberately keep lots from being processed, thereby keeping the tools idle for some time. However, there is no way for the user/operator of a tool to know if a tool with an empty dispatch list is idle by design, or if there is something that should be done to make one or more lots dispatchable at the tool.
Visibility to the logic of the dispatching rules is not available in real-time, as the service manager has been optimized for rapid execution of the dispatching rules. Understanding the reason a lot cannot be dispatched is important to fabrication operation, as once the reasons are understood, it can then be known what can be done to make an idle lot available and to better utilize the tools.
Thus, it has been determined by the present application that a need exists for a real time display to show the status of dispatched lots with explanation codes.